1. Field of the Invention
The present invention relates to an air bag apparatus for use in a vehicle, and particularly relates to an air bag apparatus having a tether for limiting the inflated shape of the air bag and a diffuser for limiting the flow of inflation gas into the air bag.
2. Description of the Related Art
Japanese Patent Publication No. Hei. 8-104195 discloses an air bag apparatus having a tether 61 with a diffuser region 63 for limiting the inflated shape of an air bag 62 and for limiting the flow of an inflation gas. The tether 61 is disposed in the air bag 62 as shown in FIGS. 10 and 11. FIG. 10 is a sectional view of the inflated air bag 62 taken along the line I--I in FIG. 11. FIG. 11 is a top plan view of the air bag 62.
In the air bag 62 disclosed in the above Publication, the tether 61 is disposed so that the periphery of the gas inlet 64 is connected to a top wall portion opposite the gas inlet 64. 67 designates an inflator.
The tether 61 is stitched to the periphery of the gas inlet 64 along a stitched region 65 of the gas inlet side of the air bag 62 so that the diffuser region 63 of the tether 61 is disposed above the gas inlet 64. A region between a non-stitched portion of the tether 61 and the periphery of the gas inlet 64 is provided as a gas communication region 66 allowing the inflation gas to flow into the air bag. In the stitched region 65, the tether 61 is extended and tether 61 is also stitched to the top wall of the air bag 62.
That is, in the air bag 62 disclosed in the above Publication, the diffuser region 63 of the tether 61 is disposed above the gas inlet 64 of the air bag 62 so that the tether 61 also limits the flow of inflation gas into the air bag 62.
When the inflation gas flows into the air bag 62 through the gas inlet 64, the inflation gas flows into the air bag 62 via the open and non-stitched gas communication region 66, such that the air bag 62 is inflated into a shape limited by the tether 61.
In such an air bag 62, however, predetermined portions of the tether 61 need to be stitched to the top wall and about the periphery of the gas inlet 64. Because the tether 61 is disposed inside the air bag 62, so that the diffuser region 63 of the tether 61 is above the gas inlet 64, it is difficult to perform the stitching work. Thus, because the stitching is difficult is perform, it is likewise difficult to dispose the tether 61 with the diffuser region 63 inside the air bag 62.